package com.mhg.hdfs.service;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.PostConstruct;

import com.alibaba.fastjson.JSON;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;
import org.apache.hadoop.hdfs.web.JsonUtil;
import org.apache.hadoop.io.IOUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;


@Component
public class HdfsService {

    @Value("${hdfs.path}")
    private String path;
    @Value("${hdfs.username}")
    private String username;

    private static String hdfsPath;
    private static String hdfsName;
    private static final int bufferSize = 1024 * 1024 * 64;

    /**
     * 获取HDFS配置信息
     * @return
     */
    private static Configuration getConfiguration() {
        Configuration configuration = new Configuration();
        configuration.set("fs.defaultFS", hdfsPath);
        return configuration;
    }

    /**
     * 获取HDFS文件系统对象
     * @return
     * @throws Exception
     */
    public static FileSystem getFileSystem() throws Exception {
        // 客户端去操作hdfs时是有一个用户身份的，默认情况下hdfs客户端api会从jvm中获取一个参数作为自己的用户身份
        // DHADOOP_USER_NAME=hadoop
        // 也可以在构造客户端fs对象时，通过参数传递进去
        FileSystem fileSystem = FileSystem.get(new URI(hdfsPath), getConfiguration(), hdfsName);
        return fileSystem;
    }

    /**
     * 在HDFS创建文件夹
     * @param path
     * @return
     * @throws Exception
     */
    public static boolean mkdir(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return false;
        }
        if (existFile(path)) {
            return true;
        }
        FileSystem fs = getFileSystem();
        // 目标路径
        Path srcPath = new Path(path);
        boolean isOk = fs.mkdirs(srcPath);
        fs.close();
        return isOk;
    }

    /**
     * 判断HDFS文件是否存在
     * @param path
     * @return
     * @throws Exception
     */
    public static boolean existFile(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return false;
        }
        FileSystem fs = getFileSystem();
        Path srcPath = new Path(path);
        boolean isExists = fs.exists(srcPath);
        return isExists;
    }

    /**
     * 读取HDFS目录信息
     * @param path
     * @return
     * @throws Exception
     */
    public static List<Map<String, Object>> readPathInfo(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return null;
        }
        if (!existFile(path)) {
            return null;
        }
        FileSystem fs = getFileSystem();
        // 目标路径
        Path newPath = new Path(path);
        FileStatus[] statusList = fs.listStatus(newPath);
        List<Map<String, Object>> list = new ArrayList<>();
        if (null != statusList && statusList.length > 0) {
            for (FileStatus fileStatus : statusList) {
                Map<String, Object> map = new HashMap<>();
                map.put("filePath", fileStatus.getPath());
                map.put("fileStatus", fileStatus.toString());
                list.add(map);
            }
            return list;
        } else {
            return null;
        }
    }

    /**
     * HDFS创建文件
     * @param path
     * @param file
     * @throws Exception
     */
    public static void createFile(String path, MultipartFile file) throws Exception {
        if (StringUtils.isEmpty(path) || null == file.getBytes()) {
            return;
        }
        String fileName = file.getOriginalFilename();
        FileSystem fs = getFileSystem();
        // 上传时默认当前目录，后面自动拼接文件的目录
        Path newPath = new Path(path + "/" + fileName);
        // 打开一个输出流
        FSDataOutputStream outputStream = fs.create(newPath);
        outputStream.write(file.getBytes());
        outputStream.close();
        fs.close();
    }

    /**
     * 读取HDFS文件内容
     * @param path
     * @return
     * @throws Exception
     */
    public static String readFile(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return null;
        }
        if (!existFile(path)) {
            return null;
        }
        FileSystem fs = getFileSystem();
        // 目标路径
        Path srcPath = new Path(path);
        FSDataInputStream inputStream = null;
        try {
            inputStream = fs.open(srcPath);
            // 防止中文乱码
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
            String lineTxt = "";
            StringBuffer sb = new StringBuffer();
            while ((lineTxt = reader.readLine()) != null) {
                sb.append(lineTxt);
            }
            return sb.toString();
        } finally {
            inputStream.close();
            fs.close();
        }
    }

    /**
     * 读取HDFS文件列表
     * @param path
     * @return
     * @throws Exception
     */
    public static List<Map<String, String>> listFile(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return null;
        }
        if (!existFile(path)) {
            return null;
        }

        FileSystem fs = getFileSystem();
        // 目标路径
        Path srcPath = new Path(path);
        // 递归找到所有文件
        RemoteIterator<LocatedFileStatus> filesList = fs.listFiles(srcPath, true);
        List<Map<String, String>> returnList = new ArrayList<>();
        while (filesList.hasNext()) {
            LocatedFileStatus next = filesList.next();
            String fileName = next.getPath().getName();
            Path filePath = next.getPath();
            Map<String, String> map = new HashMap<>();
            map.put("fileName", fileName);
            map.put("filePath", filePath.toString());
            returnList.add(map);
        }
        fs.close();
        return returnList;
    }

    /**
     * HDFS重命名文件
     * @param oldName
     * @param newName
     * @return
     * @throws Exception
     */
    public static boolean renameFile(String oldName, String newName) throws Exception {
        if (StringUtils.isEmpty(oldName) || StringUtils.isEmpty(newName)) {
            return false;
        }
        FileSystem fs = getFileSystem();
        // 原文件目标路径
        Path oldPath = new Path(oldName);
        // 重命名目标路径
        Path newPath = new Path(newName);
        boolean isOk = fs.rename(oldPath, newPath);
        fs.close();
        return isOk;
    }

    /**
     * 删除HDFS文件
     * @param path
     * @return
     * @throws Exception
     */
    public static boolean deleteFile(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return false;
        }
        if (!existFile(path)) {
            return false;
        }
        FileSystem fs = getFileSystem();
        Path srcPath = new Path(path);
        boolean isOk = fs.deleteOnExit(srcPath);
        fs.close();
        return isOk;
    }

    /**
     * 上传HDFS文件
     * @param path
     * @param uploadPath
     * @throws Exception
     */
    public static void uploadFile(String path, String uploadPath) throws Exception {
        if (StringUtils.isEmpty(path) || StringUtils.isEmpty(uploadPath)) {
            return;
        }
        FileSystem fs = getFileSystem();
        // 上传路径
        Path clientPath = new Path(path);
        // 目标路径
        Path serverPath = new Path(uploadPath);

        // 调用文件系统的文件复制方法，第一个参数是否删除原文件true为删除，默认为false
        fs.copyFromLocalFile(false, clientPath, serverPath);
        fs.close();
    }

    /**
     * 下载HDFS文件
     * @param path
     * @param downloadPath
     * @throws Exception
     */
    public static void downloadFile(String path, String downloadPath) throws Exception {
        if (StringUtils.isEmpty(path) || StringUtils.isEmpty(downloadPath)) {
            return;
        }
        FileSystem fs = getFileSystem();
        // 上传路径
        Path clientPath = new Path(path);
        // 目标路径
        Path serverPath = new Path(downloadPath);

        // 调用文件系统的文件复制方法，第一个参数是否删除原文件true为删除，默认为false
        fs.copyToLocalFile(false, clientPath, serverPath);
        fs.close();
    }

    /**
     * HDFS文件复制
     * @param sourcePath
     * @param targetPath
     * @throws Exception
     */
    public static void copyFile(String sourcePath, String targetPath) throws Exception {
        if (StringUtils.isEmpty(sourcePath) || StringUtils.isEmpty(targetPath)) {
            return;
        }
        FileSystem fs = getFileSystem();
        // 原始文件路径
        Path oldPath = new Path(sourcePath);
        // 目标路径
        Path newPath = new Path(targetPath);

        FSDataInputStream inputStream = null;
        FSDataOutputStream outputStream = null;
        try {
            inputStream = fs.open(oldPath);
            outputStream = fs.create(newPath);

            IOUtils.copyBytes(inputStream, outputStream, bufferSize, false);
        } finally {
            inputStream.close();
            outputStream.close();
            fs.close();
        }
    }

    /**
     * 打开HDFS上的文件并返回byte数组
     * @param path
     * @return
     * @throws Exception
     */
    public static byte[] openFileToBytes(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return null;
        }
        if (!existFile(path)) {
            return null;
        }
        FileSystem fs = getFileSystem();
        // 目标路径
        Path srcPath = new Path(path);
        try {
            FSDataInputStream inputStream = fs.open(srcPath);
            return IOUtils.readFullyToByteArray(inputStream);
        } finally {
            fs.close();
        }
    }

    /**
     * 打开HDFS上的文件并返回java对象
     * @param path
     * @return
     * @throws Exception
     */
    public static <T extends Object> T openFileToObject(String path, Class<T> clazz) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return null;
        }
        if (!existFile(path)) {
            return null;
        }
        String jsonStr = readFile(path);
        return JSON.parseObject(jsonStr,clazz);
        //fromObject(jsonStr, clazz);
    }

    /**
     * 获取某个文件在HDFS的集群位置
     * @param path
     * @return
     * @throws Exception
     */
    public static BlockLocation[] getFileBlockLocations(String path) throws Exception {
        if (StringUtils.isEmpty(path)) {
            return null;
        }
        if (!existFile(path)) {
            return null;
        }
        FileSystem fs = getFileSystem();
        // 目标路径
        Path srcPath = new Path(path);
        FileStatus fileStatus = fs.getFileStatus(srcPath);
        return fs.getFileBlockLocations(fileStatus, 0, fileStatus.getLen());
    }

    @PostConstruct
    public void getPath() {
        hdfsPath = this.path;
    }

    @PostConstruct
    public void getName() {
        hdfsName = this.username;
    }

    public static String getHdfsPath() {
        return hdfsPath;
    }

    public String getUsername() {
        return username;
    }
}